Extensive production of acrylamide and gamma-diketone solvents represents an environmental and occupational health threat. Molecular mechanisms of these toxicants are relevant to neurodegenerative disorders with similar pathologies or functional losses, as well as to neurobiological identification of protein function. The proposed studies are designed to evaluate the relevance of axonal transport deficiencies and neurofilament (NF) accumulation to axonal degeneration and to identify a molecular site and mode of action of transport reductions. The efficacy of fast anterograde transport (faAXT) reductions in depleting vital macromolecules in the distal axon will be determined with AVEC-DIC microscopy and immunofluorescence. The correlation between NF accumulation or faAXT reductions and degeneration will be tested in two models; crayfish which lack neurofilaments and a transgenic mouse with NF limited to the neuron soma, through a combination of video microscopy of AXT, functional testing and morphological studies. Direct action of toxicants on the motor protein kinesin will be assessed with a variety of biochemical and functional as says using reconstituted transport components in vitro as well as extruded squid axoplasm systems. Indirect action through altered phosphorylation of kinesin will be determined with immunoadsorption and 2D-electrophoresis. Potential repair of transport and prevention of neurotoxicity by a memory- enhancing drug, capable of reversing some transport block, will be determined. Collectively, these studies will greatly enhance our understanding of specific molecular alteration within axons induced by toxicants and their relationship to neurodegeneration.